Small fixes to make Github README page look better.

I'm using RST chapters and section to add some style to the project
front page on Github.
[BIG] Enforcing PEP8 on the plover/ files.

A few fixes here and there:
- lines < 80char
- spaces around operators
- unused imports and variables
- `duck` replaced with repr(duck)
- comparisons with None, True, False, replaced with "is", "is not"
Adding empty changelog to fix #17.
Merge pull request #67 from mike-perdide/cosmetic_readme

Small fixes to make Github README page look better.
Merge pull request #68 from mike-perdide/pep8_fixes

[BIG] Enforcing PEP8 on the plover/ files.
Merge pull request #69 from mike-perdide/add_changelog

Adding empty changelog to fix #17.